Vanadium dioxide temperature control film, vanadium dioxide thermochromic glass and preparation method of vanadium dioxide thermochromic glass

Abstract

The invention belongs to the field of glass surface treatment, and particularly discloses a vanadium dioxide temperature control film, vanadium dioxide thermochromic glass and a preparation method of the vanadium dioxide thermochromic glass. The preparation method of the vanadium dioxide temperature control film comprises the following steps: S1, fully mixing soluble vanadium salt, a precipitator, a dopant and water, reacting for a certain time, performing solid-liquid separation to obtain a solid phase, and fully mixing the obtained solid phase with a film-forming agent to obtain vanadium dioxide precursor slurry; s2, coating the vanadium dioxide precursor slurry on a substrate through an electrostatic spinning technology to obtain a vanadium dioxide precursor film; and S3, carrying out heat treatment on the vanadium dioxide precursor film to obtain the vanadium dioxide temperature control film. The dopant modified vanadium dioxide temperature control film is prepared through the electrostatic spinning technology and heat treatment, and the obtained film is compact, has a three-dimensional network structure, is resistant to friction and controllable in film thickness and has good stability, weather resistance and optical performance.

Description

Technical Field

[0001] The invention belongs to the field of glass surface treatment, and specifically relates to a vanadium dioxide temperature control film and a preparation method thereof, and a vanadium dioxide thermochromic glass and a preparation method thereof. Background Art

[0002] Vanadium dioxide thermochromic glass is a smart glass that uses the metal-insulator transition (MIT) characteristics of vanadium dioxide (VO2) to achieve color change. It can be used in scenes such as building surfaces, glass surfaces, and car rearview mirrors. Vanadium dioxide is a typical thermochromic material with an intrinsic phase transition temperature of 68°C. After the temperature rises to the phase transition temperature, the material changes from the monoclinic phase to the tetragonal phase in a very short time. Along with the phase change, the physical properties of vanadium dioxide undergo a sudden change. For example, while ensuring that the visible light transmittance remains basically unchanged, the vanadium dioxide film can achieve a change from high transmittance to low transmittance of near-infrared light transmittance, and the resistivity of the film will also drop by 10 2 ~10 5 Order of magnitude. When the temperature drops, vanadium dioxide will undergo a completely reversible phase change, changing the performance of the film to the initial low-temperature state, so that the above transformation process can be realized cyclically. At the same time, the phase change of vanadium dioxide can also be stimulated by other methods such as light radiation and voltage, so that it can be integrated into existing and future electrical components, and has extremely broad application prospects in the fields of optics, electricity, magnetism, etc. Due to the special nonlinear electro-optical properties of VO2 in the MIT phase change, especially the unique phase change properties and excellent performance from high transmittance to high reflectivity of infrared light before and after the phase change, vanadium dioxide has been widely used in smart glass, optical storage, laser radiation protection film, lithium battery electrodes, high-sensitivity temperature sensors, adjustable microwave switching devices, infrared light modulation materials, etc. in recent years.

[0003] However, VO2 itself has poor stability, and tetravalent vanadium is easily oxidized to pentavalent vanadium, which affects the thermochromic reaction performance. In addition, the particles are easy to agglomerate in organic media, and the film uniformity is poor. Although the common element doping process and inorganic shell coating process can make the phase transition temperature of VO2 nanoparticles close to room temperature, it will cause irreversible effects on visible light transmittance and sunlight regulation ability. In addition, the water resistance of traditional VO2 film cannot meet the long-term outdoor use of the coating. At the same time, the reaction solution and the inevitable acid contact during the later acid rain process cause a certain degree of corrosion of VO2, which seriously shortens the service life of the film and destroys the functionality of the film.

[0004] In view of this, there is still room for improvement in the field of vanadium dioxide temperature control films and vanadium dioxide thermochromic glass. Summary of the invention

[0005] The main purpose of the present invention is to address the deficiencies in the above-mentioned prior art and to provide a vanadium dioxide temperature control film, a vanadium dioxide thermochromic glass and a preparation method thereof, in order to solve the problems that VO2 coating materials are easily oxidized, have poor stability, are corroded by acid rain, have low visible light transmittance, and are difficult to meet the performance requirements of intelligent temperature control films.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions: According to a first aspect of the present invention, a method for preparing a vanadium dioxide temperature control film is provided, which comprises the following steps: S1: fully mixing a soluble vanadium salt, a precipitant, a dopant and water, reacting for a certain period of time, performing solid-liquid separation to obtain a solid phase, and fully mixing the obtained solid phase with a film-forming agent to obtain a vanadium dioxide precursor slurry; S2: coating the vanadium dioxide precursor slurry on a substrate by electrospinning technology to obtain a vanadium dioxide precursor film; S3: heat-treating the vanadium dioxide precursor film to obtain a vanadium dioxide temperature-controlled film.

[0007] According to some embodiments of the present invention, the soluble vanadium salt is one of vanadyl sulfate, vanadyl dichloride, vanadyl oxalate, vanadyl acetate, vanadyl acetylacetonate or vanadyl glycol.

[0008] According to some embodiments of the present invention, the precipitant is one of urea, ammonia water, and sodium hydroxide.

[0009] According to some embodiments of the present invention, the dopant is one or more of a tungsten dopant, a molybdenum dopant, a niobium dopant, a lanthanum dopant, a bismuth dopant, a fluorine dopant or a manganese dopant.

[0010] According to some embodiments of the present invention, the tungsten dopant is one of ammonium tungstate, tungstic acid, scheeltungstic acid, and tungsten chloride.

[0011] According to some embodiments of the present invention, the molybdenum dopant is one of ammonium molybdate and molybdic acid.

[0012] According to some embodiments of the present invention, the film-forming agent is a mixture of polyvinyl pyrrolidone, ethanol, isopropanol and ethylene glycol.

[0013] According to some embodiments of the present invention, step S1 further includes: dispersing the soluble vanadium salt in water to obtain a vanadium liquid; adding the precipitant to the vanadium liquid, heating to 80-120° C., stirring for 1-5 hours to obtain a suspension; adding the dopant to the suspension, reacting for a certain time, and obtaining a solid phase through solid-liquid separation; mixing the solid phase with the film-forming agent, stirring for a certain time, and obtaining the vanadium dioxide precursor slurry.

[0014] According to some embodiments of the present invention, step S2 further includes: loading the vanadium dioxide precursor slurry into a syringe of an electrospinning device, fixing the substrate on an electrospinning table of the electrospinning device, and performing electrospinning; after the electrospinning is completed, drying the substrate to obtain the vanadium dioxide precursor film.

[0015] According to some embodiments of the present invention, step S3 further comprises: placing the vanadium dioxide precursor film in a vacuum furnace, calcining at 500-700° C. for 1-4 hours at a heating rate of 5-9° C. / min, and cooling along with the furnace to obtain the vanadium dioxide temperature-controlled film.

[0016] According to some embodiments of the present invention, the concentration of the vanadium solution is 1-2.5 mol / L.

[0017] According to some embodiments of the present invention, the molar ratio of the precipitant to the soluble vanadium salt is 1:1-8:1.

[0018] According to some embodiments of the present invention, the molar ratio of the dopant to the soluble vanadium salt is 1:25-1:10.

[0019] According to some embodiments of the present invention, during the electrospinning process, the thickness of the needle of the electrospinning device is 0.1-0.8 mm, the distance between the needle and the electrospinning table is 8-12 cm, and the voltage between the needle and the electrospinning table is 8-16 kV; during the drying process, the drying temperature is 40-60°C, and the drying time is 10-18 h.

[0020] According to some embodiments of the present invention, in the film-forming agent, the molar concentration of polyvinyl pyrrolidone is 0.5-3 mol / L, and the volume ratio of ethanol, isopropanol and ethylene glycol is 1:(1-2):(3-8).

[0021] According to some embodiments of the present invention, the soluble vanadium salt is vanadium sulfate, the precipitant is urea, the dopant is a tungsten dopant and a molybdenum dopant, the molar ratio of the tungsten dopant to the molybdenum dopant is 1:1-8:1, the tungsten dopant is ammonium tungstate, and the molybdenum dopant is ammonium molybdate.

[0022] According to a second aspect of the present invention, there is provided a vanadium dioxide temperature control film, which is prepared by the preparation method described in the first aspect of the present invention.

[0023] According to a third aspect of the present invention, a method for preparing vanadium dioxide thermochromic glass is provided, comprising the following steps: S10: forming a vanadium dioxide temperature control film on a glass substrate using the preparation method described in the first aspect of the present invention; S20: coating a mixture of methyl methacrylate and acrylic acid on the vanadium dioxide temperature control film, and forming a transparent protective film through ultraviolet light exposure to obtain vanadium dioxide thermochromic glass.

[0024] According to some embodiments of the present invention, in the mixture of methyl methacrylate and acrylic acid, the volume ratio of the methyl methacrylate to the acrylic acid is 1:1-5:1.

[0025] According to some embodiments of the present invention, the coating thickness of the mixture is 100-500 μm.

[0026] According to some embodiments of the present invention, the ultraviolet irradiation time is 3-10 min.

[0027] According to a fourth aspect of the present invention, there is provided a vanadium dioxide thermochromic glass, which is prepared by the preparation method described in the third aspect of the present invention.

[0028] By adopting the above technical solution, the present invention has the following beneficial effects: The method for preparing a vanadium dioxide temperature control film provided by the present invention first prepares a vanadium dioxide precursor slurry doped with a dopant, then coats the vanadium dioxide precursor slurry onto a substrate by electrostatic spinning technology, and then obtains a vanadium dioxide temperature control film by heat treatment. In the method of the present invention, by doping with a dopant, the phase transition temperature of vanadium dioxide can be effectively reduced, and thermal hysteresis can also be reduced; by adopting electrostatic spinning technology for film coating, the film is made dense and has a three-dimensional network structure, the friction resistance is improved, the film thickness is controllable, and the film coating can be performed according to demand. The method of the present invention has simple raw materials, low equipment requirements, low preparation cost, and a simple preparation process. The vanadium dioxide temperature control film thus prepared has a low phase transition temperature and good wear resistance.

[0029] The method for preparing vanadium dioxide thermochromic glass provided by the present invention first prepares a vanadium dioxide temperature control film on a glass substrate, and then prepares a transparent protective film on the vanadium dioxide temperature control film, thereby obtaining the vanadium dioxide thermochromic glass. In addition to the advantages of the method for preparing the vanadium dioxide temperature control film described above, the method of the present invention also forms a transparent protective film on the outside of the vanadium dioxide temperature control film, which has a certain protective effect on the inner vanadium dioxide temperature control film without affecting the transmittance, thereby extending the life of the inner vanadium dioxide temperature control film, giving it super-hydrophobic properties, enhancing self-cleaning ability, and avoiding acid rain corrosion. The method of the present invention can directly and effectively solve the problems that VO2 coating materials are easily oxidized, have poor thermochromic weathering stability, have limited durability, are easily corroded by acid rain, and the like. The vanadium dioxide thermochromic glass prepared by the method of the present invention has good temperature control ability, good stability, weathering resistance, optical properties, and super hydrophobic self-cleaning properties. The particles have good dispersibility in organic dispersion media, uniform film formation, and high visible light transmittance. The performance is far superior to the thin film materials containing vanadium dioxide particles commonly found on the market. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 The present invention provides a flow chart of a method for preparing a vanadium dioxide temperature control film.

[0031] Figure 2 The present invention provides a flow chart of a method for preparing vanadium dioxide thermochromic glass.

[0032] Figure 3 The top view of the vanadium dioxide thermochromic glass prepared by the method for preparing the vanadium dioxide thermochromic glass provided by the present invention is shown. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0034] As required, specific embodiments of the present invention are disclosed in the present specification; however, it should be understood that the embodiments disclosed herein are merely examples of the present invention that can be implemented in multiple, alternative forms. In the following description, multiple operating parameters and components are described in multiple embodiments contemplated. These specific parameters and components are only used as examples in this specification and are not meant to be limiting.

[0035] Vanadium dioxide thermochromic glass is an intelligent temperature film material that has the function of autonomously regulating infrared radiation as it changes with temperature. It brings good news to effective energy saving in buildings. As the ambient temperature changes, it can achieve reversible conversion between a low-temperature infrared high transmittance state and a high-temperature infrared high barrier state, regulate the solar radiation energy entering the room, and effectively reduce air conditioning and heating energy consumption. However, the current VO2 phase transition temperature is 68°C, which is much higher than the suitable temperature for human habitation. Therefore, it is necessary to lower its phase transition temperature to a suitable temperature for human habitation. At the same time, the current better VO2 film has a low visible light transmittance due to in-band absorption, and the visible light transmittance is about 60%, which restricts the application of such glass in intelligent temperature-controlled windows and buildings. To this end, the present invention proposes a vanadium dioxide temperature control film, a vanadium dioxide thermochromic glass and a preparation method thereof.

[0036] The first aspect of the present invention provides a method for preparing a vanadium dioxide temperature control film, such as Figure 1 As shown, the method includes the following steps: S1: fully mixing a soluble vanadium salt, a precipitant, a dopant and water, reacting for a certain period of time, separating the solid from the liquid to obtain a solid phase, and fully mixing the obtained solid phase with a film-forming agent to obtain a vanadium dioxide precursor slurry; S2: coating the vanadium dioxide precursor slurry on a substrate by electrostatic spinning technology to obtain a vanadium dioxide precursor film; S3: heat treating the vanadium dioxide precursor film to obtain a vanadium dioxide temperature-control film.

[0037] The method for preparing the vanadium dioxide temperature control film provided by the present invention first prepares a vanadium dioxide precursor slurry doped with a dopant, then coats the vanadium dioxide precursor slurry onto a substrate by electrostatic spinning technology, and then obtains the vanadium dioxide temperature control film by heat treatment. In the method of the present invention, by doping with a dopant, the phase transition temperature of vanadium dioxide can be effectively reduced, and thermal hysteresis can also be reduced; by adopting electrostatic spinning technology for film coating, the film is made dense and has a three-dimensional network structure, the friction resistance is improved, the film thickness is controllable, and the film coating can be performed according to demand. The method of the present invention has simple raw materials, low equipment requirements, low preparation cost, and a simple preparation process.

[0038] The present invention is described in detail below in conjunction with each step.

[0039] In step S1, by adding a dopant during the preparation of the vanadium dioxide precursor slurry, the purpose is to introduce doping elements into the vanadium dioxide precursor slurry to dope the vanadium dioxide, so as to effectively reduce the phase transition temperature of vanadium dioxide and also reduce thermal hysteresis; by adding a precipitant, the purpose is to react with a soluble vanadium salt to precipitate a vanadium dioxide precursor; by adding a film-forming agent, the purpose is to facilitate the implementation of the subsequent film-forming process.

[0040] In the scheme of the present invention, the soluble vanadium salt is a vanadium salt that can be dissolved in water so as to react with a precipitant to precipitate a vanadium dioxide precursor. Preferably, the soluble vanadium salt can be one of vanadyl sulfate, vanadyl dichloride, vanadyl oxalate, vanadyl acetate, vanadyl acetylacetonate, vanadyl glycol or other tetravalent vanadium salts.

[0041] In the solution of the present invention, the precipitant is a substance that can react with a soluble vanadium salt to precipitate a vanadium dioxide precursor. Preferably, the precipitant can be one of urea, ammonia water, sodium hydroxide or other substances that can provide hydroxide.

[0042] In the solution of the present invention, the dopant is a substance that can be doped with vanadium dioxide to reduce the phase transition temperature of vanadium dioxide. The dopant is one or more of a tungsten dopant, a molybdenum dopant, a niobium dopant, a lanthanum dopant, a bismuth dopant, a fluorine dopant or a manganese dopant. The dopant is a soluble salt containing the above doping elements that can be dissolved in water. For example, the tungsten dopant can be one of ammonium tungstate, tungstic acid, tungstic acid, and tungsten chloride, and the molybdenum dopant can be one of ammonium molybdate and molybdic acid.

[0043] In the scheme of the present invention, the film-forming agent is a substance that promotes plastic flow and elastic deformation of the precursor slurry, improves the agglomeration performance, and can form a film within a certain temperature range. In some embodiments, the film-forming agent can be a mixture of polyvinyl pyrrolidone (PVP), ethanol, isopropanol, and ethylene glycol. In addition to the film-forming effect, it can be used as a powder dispersion solvent. Preferably, in the film-forming agent, the solid molar concentration is controlled between 0.5-3M, that is, the molar concentration of polyvinyl pyrrolidone (that is, the ratio of the number of moles of polyvinyl pyrrolidone to the total volume of ethanol, isopropanol, and ethylene glycol) is 0.5-3mol / L, wherein the volume of ethanol, isopropanol, and ethylene glycol is 1: (1-2): (3-8). In some other embodiments, other types of film-forming agents can also be used.

[0044] In some embodiments, step S1 further comprises: dispersing a soluble vanadium salt in water to obtain a vanadium liquid; adding a precipitant to the vanadium liquid, heating to 80-120°C, stirring for 1-5 hours to obtain a suspension; adding a dopant to the suspension, reacting for a certain time, and obtaining a solid phase through solid-liquid separation; adding a film-forming agent to the solid phase, stirring for a certain time to obtain a vanadium dioxide precursor slurry. In the present invention, the vanadium liquid is first reacted with the precipitant to generate a vanadium precipitate; then the dopant is added to dope the doping element into the generated vanadium precipitate; solid-liquid separation is used to separate the doped vanadium precipitate from the liquid phase; then, the doped vanadium precipitate is dispersed in the film-forming agent to form a vanadium dioxide precursor slurry.

[0045] Preferably, the molar concentration of the vanadium solution is 1-2.5 mol / L.

[0046] Preferably, the molar ratio of the precipitant to the soluble vanadium salt is 1:1-8:1.

[0047] Preferably, the molar ratio of the dopant to the soluble vanadium salt is 1:25-1:10.

[0048] In a preferred embodiment, in step S1, the soluble vanadium salt is vanadyl sulfate, the precipitant is urea, the dopant is tungsten dopant and molybdenum dopant, the molar ratio of tungsten dopant to molybdenum dopant is 1:1-8:1, the tungsten dopant is ammonium tungstate, the molybdenum dopant is ammonium molybdate, the film-forming agent is a mixture of polyvinyl pyrrolidone, ethanol, isopropanol, and ethylene glycol, the molar concentration of polyvinyl pyrrolidone is 0.5-3 mol / L, and the volume ratio of ethanol, isopropanol, and ethylene glycol is 1:(1-2):(3-8).

[0049] In step S2, a vanadium dioxide precursor film is formed on a substrate by electrospinning technology. The film formed in this way is dense and has a three-dimensional network structure, is friction-resistant, and has a controllable film thickness, and can be plated according to demand. The electrospinning technology has a low coating cost, the fiber diameter can be adjusted, and the film preparation is relatively simple.

[0050] Electrospinning technology has the advantages of simple equipment, low cost and controllable process, and has become one of the main methods for effectively preparing micron and nano materials. Since 1934, this method has been widely used in the preparation of metal oxide nanofibers, polymer nanofibers and other anisotropic nanostructures. Compared with other complex film-forming methods, electrospinning can quickly synthesize large-area nanofibers in a very short time, and the fibers have the advantages of large specific surface area, high porosity, good uniformity and easy film formation. Moreover, this electrospinning device is simple and mainly consists of three parts: a high-voltage DC power supply, a syringe and an electrospinning table.

[0051] In some embodiments, step S2 further comprises: loading the vanadium dioxide precursor slurry into a syringe of an electrospinning device, fixing the substrate on an electrospinning table of the electrospinning device, and performing electrospinning; after the electrospinning is completed, drying the substrate to obtain a vanadium dioxide precursor film. During the electrospinning process, the spinning process is controlled by controlling the distance between the needle of the electrospinning device and the electrospinning table and the voltage between the needle and the electrospinning table.

[0052] Preferably, during the electrospinning process, the thickness of the needle is 0.1-0.8 mm, the distance between the needle and the electrospinning table is 8-12 cm, and the voltage between the needle and the electrospinning table is 8-16 kV.

[0053] In some embodiments, the substrate is dried by placing it in a drying oven. Preferably, the drying temperature is 40-60° C. and the drying time is 10-18 hours.

[0054] In step S3, the vanadium dioxide precursor film is heat-treated to convert the vanadium dioxide precursor into vanadium dioxide.

[0055] In some embodiments, step S3 further includes: placing the vanadium dioxide precursor film in a vacuum furnace, calcining at 500-700° C. for 1-4 hours, with a heating rate of 5-9° C. / min, and cooling along with the furnace to obtain a vanadium dioxide temperature-controlled film.

[0056] In a preferred embodiment, a method for preparing a vanadium dioxide temperature control film comprises the following steps: (1) Preparation of vanadium dioxide precursor slurry: A certain amount of vanadium sulfate powder is dispersed in a certain amount of deionized water, and the molar concentration is controlled at 1-2.5M; then a certain amount of urea is added as a precipitant, and the molar ratio of the precipitant to the vanadium sulfate is 1:1-8:1, and then heated to 100°C and stirred for 1-5h to form a suspension with precipitation; ammonium tungstate (NH4) is added dropwise during the stirring process. 10 A mixed solution of H2(W2O7)6 and ammonium molybdate (NH4)6Mo7O4•4H2O, the ratio of the total molar amount of tungsten and molybdenum to the molar amount of vanadium element is 1:25-1:10, and the molar ratio of tungsten to molybdenum is (1:1-8:1); after filtering the solid, directly add it into a mixed solution of polyvinyl pyrrolidone (PVP), isopropanol, ethanol, and ethylene glycol, wherein the molar concentration of the solid is controlled between 0.5 and 3M, and the ratio of ethanol, isopropanol, and ethylene glycol is 1: (1-2): (3-8), and then ultrasonically stirred for 15min-80min to obtain vanadium dioxide precursor slurry A.

[0057] Principle: The purpose of adding a mixed solution of ammonium tungstate (NH4)10H2(W2O7)6 and ammonium molybdate (NH4)6Mo7O4•4H2O is to introduce tungsten and molybdenum elements for doping. The elements are doped in the atomic gaps, which is equivalent to microscopic modification, which can effectively reduce the phase transition temperature of vanadium dioxide. At the same time, the thermal hysteresis is also small. The bound water and nitrogen elements will be released from the matrix in the form of ammonia during the later calcination process.

[0058] (2) Preparation of vanadium dioxide precursor film: Take a certain amount of vanadium dioxide precursor slurry A (3ml-10ml) and put it into a plastic syringe. Install a plastic capillary at the front end of the syringe with a needle thickness of 0.1-0.8mm. Fix the glass substrate on the electrospinning table with the needle 8-12cm away from the electrospinning table. The voltage is controlled at 8-16kV. After spinning, put the substrate into a vacuum drying oven and dry it at 40-60℃ for 10-18h to obtain the vanadium dioxide precursor film B.

[0059] Principle: The electrospinning technology is used to coat the substrate. The film is dense and has a three-dimensional mesh structure that is resistant to friction. The film thickness is controllable and can be coated according to demand. This technology has a low coating cost, the fiber diameter can be adjusted, and the film preparation is relatively simple.

[0060] (3) Preparation of vanadium dioxide temperature control film: Put the substrate of vanadium dioxide precursor film B obtained in the previous step into a vacuum tube furnace, calcine at 500-700°C for 1-4h, with a heating rate of 5-9°C / min, and cool down with the furnace to obtain a vanadium dioxide temperature-controlled film.

[0061] Principle: In this stage, the vanadium dioxide precursor is converted into vanadium dioxide mainly through heat treatment.

[0062] The second aspect of the present invention provides a vanadium dioxide temperature control film prepared by the preparation method described in the first aspect of the present invention. The vanadium dioxide temperature control film provided by the present invention has a low phase change temperature and good wear resistance. When it is applied to window glass, when the temperature is low, the vanadium dioxide temperature control film is highly transparent to sunlight, allowing the sun to pass through the vanadium dioxide temperature control film to heat and insulate the room; when the temperature is high, the vanadium dioxide temperature control film is transparent to the visible band and reflects the near-infrared band, thereby achieving the purpose of making the room cool.

[0063] The third aspect of the present invention provides a method for preparing vanadium dioxide thermochromic glass, such as Figure 2 As shown, the preparation method comprises the following steps: S10: forming a vanadium dioxide temperature control film on a glass substrate by adopting the preparation method described in the first aspect of the present invention; S20: coating a mixture of methyl methacrylate and acrylic acid on the vanadium dioxide temperature control film, forming a transparent protective film through ultraviolet light, and obtaining vanadium dioxide thermochromic glass.

[0064] In step S20, during the ultraviolet irradiation process, methyl methacrylate and acrylic acid undergo a polymerization reaction, and the formed transparent protective film has a certain effect of preventing VO2 from being oxidized.

[0065] The method for preparing vanadium dioxide thermochromic glass provided by the present invention first prepares a vanadium dioxide temperature control film on a glass substrate, and then prepares a transparent protective film on the vanadium dioxide temperature control film, thereby obtaining the vanadium dioxide thermochromic glass. In addition to the advantages of the method for preparing the vanadium dioxide temperature control film described above, the method of the present invention also forms a transparent protective film on the outside of the vanadium dioxide temperature control film, which has a certain protective effect on the inner vanadium dioxide temperature control film without affecting the transmittance, thereby extending the life of the inner vanadium dioxide temperature control film, giving it super-hydrophobic properties, enhancing self-cleaning ability, and avoiding acid rain corrosion.

[0066] Preferably, in the mixture of methyl methacrylate and acrylic acid, the volume ratio of methyl methacrylate to acrylic acid is 1:1-5:1. Preferably, the coating thickness of the mixture is 100-500 μm.

[0067] Preferably, the ultraviolet irradiation time is 3-10 min.

[0068] The fourth aspect of the present invention provides a vanadium dioxide thermochromic glass prepared by the preparation method described in the third aspect of the present invention. The vanadium dioxide thermochromic glass provided by the present invention has good temperature control ability, good stability, weather resistance, optical properties, and super hydrophobic self-cleaning properties. The particles have good dispersibility in the organic dispersion medium, uniform film formation, and high visible light transmittance. The performance is far superior to the thin film materials containing vanadium dioxide particles commonly found on the market. The vanadium dioxide thermochromic glass provided by the present invention has a low-temperature visible light transmittance of more than 74%, a high-temperature visible light transmittance of more than 70%, and a sunlight regulation efficiency of more than 15.3%. After aging at high temperature and high humidity for 240 hours, the low-temperature visible light transmittance is more than 76%, the high-temperature visible light transmittance is more than 71%, and the sunlight regulation efficiency is more than 14%.

[0069] Figure 3 This is a top view of the vanadium dioxide thermochromic glass prepared by the present invention. It is only a schematic diagram and does not limit the number of functional powders loaded with vanadium dioxide, the density of electrospun fibers and the spinning direction. 1 is a glass base plate, 2 is an electrospun vanadium dioxide mixed fiber body, and 3 is vanadium dioxide particles doped with tungsten and molybdenum elements.

[0070] The present invention is further described below in conjunction with specific examples, but the present invention is not limited in any way. To avoid redundant description, the methods used are all conventional methods unless otherwise specified.

[0071] Embodiment 1: Step 1: A certain amount of vanadium sulfate powder is dispersed in a certain amount of deionized water, and the molar concentration is controlled at 1M; then a certain amount of urea is added as a precipitant, and the molar ratio of the precipitant to vanadium sulfate is 4:1, and then heated to 100°C and stirred for 2 hours to form a suspension with precipitation; ammonium tungstate (NH4) is added dropwise during the stirring process. 10 A mixed solution of H2(W2O7)6 and ammonium molybdate (NH4)6Mo7O4•4H2O, the total molar amount of tungsten and molybdenum and the molar amount of vanadium element is 1:20, and the molar ratio of tungsten to molybdenum is (1:1). After filtering the solid, directly add a mixed solution of polyvinyl pyrrolidone (PVP), isopropanol, ethanol, and ethylene glycol, wherein the solid molar concentration is controlled at about 2M, and the ratio of ethanol, isopropanol, and ethylene glycol is (1:1:8), and then ultrasonically stirred for 20 minutes to obtain vanadium dioxide precursor slurry A.

[0072] Step 2: Take a certain amount of vanadium dioxide precursor slurry A (8ml) in a plastic syringe, install a plastic capillary at the front end of the syringe, the needle thickness is 0.5mm, fix the glass substrate on the electrospinning table, the needle is 10cm away from the spinning table, the voltage is controlled at 10kV, and after spinning, put the substrate into a vacuum drying oven and dry it at 45℃ for 12h. Then, the vanadium dioxide precursor film B can be obtained.

[0073] Step 3: The substrate of the vanadium dioxide precursor film B obtained in the previous step was placed in a vacuum tube furnace, calcined at 550°C for 2 hours, with a heating rate of 8°C / min, cooled with the furnace, and a layer of methyl methacrylate and acrylic acid mixture (mixing ratio of 2:1) with a thickness of 200μm was applied on the surface, and then exposed to ultraviolet light for 5 minutes. Finally, a highly transparent vanadium dioxide thermochromic glass was obtained.

[0074] Step 4: In order to test the effect of this glass plate, relevant performance tests are required. The static contact angle of the coated surface is 150°, it has super hydrophobic properties and a certain self-cleaning function, the low-temperature visible light transmittance is 74%, the high-temperature visible light transmittance is 70%, and the sunlight regulation efficiency is 16.2%. After aging at high temperature and high humidity for 240 hours, the static contact angle of the film surface is still 143°, the low-temperature visible light transmittance is 76%, the high-temperature visible light transmittance is 72%, and the sunlight regulation efficiency is 14.9%.

[0075] Embodiment 2: Step 1: A certain amount of vanadium sulfate powder is dispersed in a certain amount of deionized water, and the molar concentration is controlled at 1.5M; then a certain amount of urea is added as a precipitant, and the molar ratio of the precipitant to vanadium sulfate is 5:1, and then heated to 100°C and stirred for 2.5h to form a suspension with precipitation; ammonium tungstate (NH4) is added dropwise during the stirring process. 10 A mixed solution of H2(W2O7)6 and ammonium molybdate (NH4)6Mo7O4•4H2O, the ratio of the total molar amount of tungsten and molybdenum to the molar amount of vanadium element is 1:22, and the molar ratio of tungsten to molybdenum is (2:1); after filtering the solid, it is directly added into a mixed solution of polyvinyl pyrrolidone (PVP), isopropanol, ethanol and ethylene glycol, wherein the molar concentration of the solid is controlled between 1M, and the ratio of ethanol, isopropanol and ethylene glycol is (1:1:6), and then ultrasonically stirred for 30 minutes to obtain vanadium dioxide precursor slurry A.

[0076] Step 2: Take a certain amount of vanadium dioxide precursor slurry A (10ml) in a plastic syringe, install a plastic capillary at the front end of the syringe, the needle thickness is 0.1mm, fix the glass substrate on the electrospinning table, the needle is 10cm away from the spinning table, the voltage is controlled at 12kV, and after spinning, put the substrate into a vacuum drying oven and dry it at 50℃ for 10h. Then, the vanadium dioxide precursor film B can be obtained.

[0077] Step 3: The substrate of the vanadium dioxide precursor film B obtained in the previous step was placed in a vacuum tube furnace, calcined at 600°C for 2 hours, with a heating rate of 8°C / min, cooled with the furnace, and a layer of a mixture of methyl methacrylate and acrylic acid (mixing ratio of 2:1) with a thickness of 100μm was applied on the surface, and then exposed to ultraviolet light for 6 minutes. Finally, a highly transparent vanadium dioxide thermochromic glass was obtained.

[0078] Step 4: To test the effect, relevant performance tests are required. The static contact angle of the film surface is 152°, with super hydrophobic properties and certain self-cleaning functions, low-temperature visible light transmittance of 76%, high-temperature visible light transmittance of 71%, and sunlight regulation efficiency of 15.4%. After aging at high temperature and high humidity for 240 hours, the static contact angle of the film surface is still 148°, the low-temperature visible light transmittance is 78%, the high-temperature visible light transmittance is 73%, and the sunlight regulation efficiency is 14.2%.

[0079] Embodiment 3: Step 1: A certain amount of vanadium sulfate powder is dispersed in a certain amount of deionized water, and the molar concentration is controlled at 2M; then a certain amount of urea is added as a precipitant, and the molar ratio of the precipitant to vanadium sulfate is 6:1, and then heated to 100°C and stirred for 2.5 hours to form a suspension with precipitation; ammonium tungstate (NH4) is added dropwise during the stirring process. 10 A mixed solution of H2(W2O7)6 and ammonium molybdate (NH4)6Mo7O4•4H2O, the ratio of the total molar amount of tungsten and molybdenum to the molar amount of vanadium element is 1:18, and the molar ratio of tungsten to molybdenum is (7:1); after filtering the solid, it is directly added into a mixed solution of polyvinyl pyrrolidone (PVP), isopropanol, ethanol and ethylene glycol, wherein the molar concentration of the solid is controlled between 2.5M, and the ratio of ethanol, isopropanol and ethylene glycol is (1:2:3), and then ultrasonically stirred for 60 minutes to obtain vanadium dioxide precursor slurry A.

[0080] Step 2: Take a certain amount of vanadium dioxide precursor slurry A (10ml) in a plastic syringe, install a plastic capillary at the front end of the syringe, the needle thickness is 0.2mm, fix the glass substrate on the electrospinning table, the needle is 10cm away from the spinning table, the voltage is controlled at 12kV, and after spinning, put the substrate into a vacuum drying oven and dry it at 40℃ for 18h. Then, the vanadium dioxide precursor film B can be obtained.

[0081] Step 3: The substrate of the vanadium dioxide precursor film B obtained in the previous step was placed in a vacuum tube furnace, calcined at 600°C for 2 hours, with a heating rate of 7°C / min, cooled with the furnace, and a layer of a mixture of methyl methacrylate and acrylic acid (mixing ratio of 5:1) with a thickness of 100μm was applied on the surface, and then exposed to ultraviolet light for 6 minutes. Finally, a highly transparent vanadium dioxide thermochromic glass was obtained.

[0082] Step 4: In order to detect the effect of the film, relevant performance tests are required. The static contact angle of the film surface is 158°, it has super hydrophobic properties and certain self-cleaning functions, low-temperature visible light transmittance is 75%, high-temperature visible light transmittance is 72%, and the sunlight regulation efficiency is 15.3%. After aging at high temperature and high humidity for 240 hours, the static contact angle of the film surface is still 150°, the low-temperature visible light transmittance is 77%, the high-temperature visible light transmittance is 71%, and the sunlight regulation efficiency is 14.2%.

[0083] Embodiment 4: Step 1: A certain amount of vanadium sulfate powder is dispersed in a certain amount of deionized water, and the molar concentration is controlled at 2.5M; then a certain amount of urea is added as a precipitant, and the molar ratio of the precipitant to vanadium sulfate is 1:1, and then heated to 80°C and stirred for 5 hours to form a suspension with precipitation; ammonium tungstate (NH4) is added dropwise during the stirring process. 10 A mixed solution of H2(W2O7)6 and ammonium molybdate (NH4)6Mo7O4•4H2O, the total molar amount of tungsten and molybdenum and the molar amount of vanadium element is 1:10, and the molar ratio of tungsten to molybdenum is (8:1). After filtering the solid, directly add a mixed solution of polyvinyl pyrrolidone (PVP), isopropanol, ethanol, and ethylene glycol, wherein the solid molar concentration is controlled at about 3M, and the ratio of ethanol, isopropanol, and ethylene glycol is (1:2:3), and then ultrasonically stirred for 15 minutes to obtain vanadium dioxide precursor slurry A.

[0084] Step 2: Take a certain amount of vanadium dioxide precursor slurry A (6ml) in a plastic syringe, install a plastic capillary at the front end of the syringe, the needle thickness is 0.8mm, fix the glass substrate on the electrospinning table, the needle is 8cm away from the spinning table, the voltage is controlled at 16kV, and after spinning, put the substrate into a vacuum drying oven and dry it at 60℃ for 12h. Then, the vanadium dioxide precursor film B can be obtained.

[0085] Step 3: The substrate of the vanadium dioxide precursor film B obtained in the previous step was placed in a vacuum tube furnace, calcined at 650°C for 1 hour, with a heating rate of 5°C / min, cooled with the furnace, and a layer of a mixture of methyl methacrylate and acrylic acid (mixing ratio of 2:1) with a thickness of 300μm was applied on the surface, and then exposed to ultraviolet light for 3 minutes. Finally, a highly transparent vanadium dioxide thermochromic glass was obtained.

[0086] Step 4: In order to test the effect of this glass plate, relevant performance tests are required. The static contact angle of the coated surface is 153°, with super hydrophobic properties and certain self-cleaning functions, low-temperature visible light transmittance of 76%, high-temperature visible light transmittance of 71%, and sunlight regulation efficiency of 15.7%. After aging at high temperature and high humidity for 240 hours, the static contact angle of the film surface is still 147°, the low-temperature visible light transmittance is 78%, the high-temperature visible light transmittance is 73%, and the sunlight regulation efficiency is 14.6%.

[0087] Embodiment 5: Step 1: A certain amount of vanadium sulfate powder is dispersed in a certain amount of deionized water, and the molar concentration is controlled at 1M; then a certain amount of urea is added as a precipitant, and the molar ratio of the precipitant to vanadium sulfate is 8:1, and then heated to 120°C and stirred for 1h to form a suspension with precipitation; ammonium tungstate (NH4) is added dropwise during the stirring process. 10 A mixed solution of H2(W2O7)6 and ammonium molybdate (NH4)6Mo7O4•4H2O, the total molar amount of tungsten and molybdenum and the molar amount of vanadium element is 1:25, and the molar ratio of tungsten to molybdenum is (4:1). After filtering the solid, directly add a mixed solution of polyvinyl pyrrolidone (PVP), isopropanol, ethanol, and ethylene glycol, wherein the solid molar concentration is controlled at about 0.5M, and the ratio of ethanol, isopropanol, and ethylene glycol is (1:1:8), and then ultrasonically stirred for 80 minutes to obtain vanadium dioxide precursor slurry A.

[0088] Step 2: Take a certain amount of vanadium dioxide precursor slurry A (3ml) in a plastic syringe, install a plastic capillary at the front end of the syringe, the needle thickness is 0.5mm, fix the glass substrate on the electrospinning table, the needle is 12cm away from the spinning table, the voltage is controlled at 8kV, and after spinning, put the substrate into a vacuum drying oven and dry it at 50℃ for 12h. Then the vanadium dioxide precursor film B can be obtained.

[0089] Step 3: The substrate of the vanadium dioxide precursor film B obtained in the previous step was placed in a vacuum tube furnace, calcined at 700°C for 4 hours, with a heating rate of 9°C / min, cooled with the furnace, and a layer of a mixture of methyl methacrylate and acrylic acid (mixing ratio of 2:1) with a thickness of 500μm was applied on the surface, and then exposed to ultraviolet light for 10 minutes. Finally, a highly transparent vanadium dioxide thermochromic glass was obtained.

[0090] Step 4: In order to test the effect of this glass plate, relevant performance tests are required. The static contact angle of the coated surface is 154°, with super hydrophobic properties and certain self-cleaning functions, low-temperature visible light transmittance of 75%, high-temperature visible light transmittance of 71%, and sunlight regulation efficiency of 15.8%. After aging at high temperature and high humidity for 240 hours, the static contact angle of the film surface is still 145°, the low-temperature visible light transmittance is 77%, the high-temperature visible light transmittance is 72%, and the sunlight regulation efficiency is 14.5%.

[0091] Finally, it should be noted that the embodiments described above are only some embodiments of the present invention, not all embodiments. The detailed description of the embodiments of the present invention is not intended to limit the scope of the invention claimed for protection, but only represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

Claims

1. A method for preparing a vanadium dioxide temperature control film, characterized in that: The following steps are involved: S1: fully mixing a soluble vanadium salt, a precipitant, a dopant and water, reacting for a certain period of time, performing solid-liquid separation to obtain a solid phase, and fully mixing the obtained solid phase with a film-forming agent to obtain a vanadium dioxide precursor slurry; S2: coating the vanadium dioxide precursor slurry on a substrate by electrospinning technology to obtain a vanadium dioxide precursor film; S3: heat-treating the vanadium dioxide precursor film to obtain a vanadium dioxide temperature-controlled film.

2. The method for preparing the vanadium dioxide temperature control film according to claim 1, characterized in that: The soluble vanadium salt is one of vanadyl sulfate, vanadyl dichloride, vanadyl oxalate, vanadyl acetate, vanadyl acetylacetonate or vanadyl ethylene glycol; The precipitant is one of urea, ammonia water and sodium hydroxide; The dopant is one or more of a tungsten dopant, a molybdenum dopant, a niobium dopant, a lanthanum dopant, a bismuth dopant, a fluorine dopant or a manganese dopant; The film-forming agent is a mixture of polyvinyl pyrrolidone, ethanol, isopropanol and ethylene glycol.

3. The method for preparing the vanadium dioxide temperature control film according to claim 1 or 2, characterized in that: Step S1 further comprises: dispersing the soluble vanadium salt in water to obtain a vanadium liquid; adding the precipitant to the vanadium liquid, heating to 80-120° C., stirring for 1-5 hours to obtain a suspension; adding the dopant to the suspension, reacting for a certain time, and obtaining a solid phase through solid-liquid separation; mixing the solid phase with the film-forming agent, stirring for a certain time, and obtaining the vanadium dioxide precursor slurry. Step S2 further comprises: loading the vanadium dioxide precursor slurry into a syringe of an electrospinning device, fixing the substrate on an electrospinning table of the electrospinning device, and performing electrospinning; after the electrospinning is completed, drying the substrate to obtain the vanadium dioxide precursor film. Step S3 further includes: placing the vanadium dioxide precursor film in a vacuum furnace, calcining at 500-700° C. for 1-4 hours, with a heating rate of 5-9° C. / min, and cooling along with the furnace to obtain the vanadium dioxide temperature-controlled film.

4. The method for preparing the vanadium dioxide temperature control film according to claim 3, characterized in that: The concentration of the vanadium solution is 1-2.5 mol / L; The molar ratio of the precipitant to the soluble vanadium salt is 1:1-8:1; The molar ratio of the dopant to the soluble vanadium salt is 1:25-1:10; During the electrospinning process, the thickness of the needle of the electrospinning device is 0.1-0.8 mm, the distance between the needle and the electrospinning table is 8-12 cm, and the voltage between the needle and the electrospinning table is 8-16 kV; During the drying process, the drying temperature is 40-60°C and the drying time is 10-18h.

5. The method for preparing the vanadium dioxide temperature control film according to claim 2, characterized in that: In the film-forming agent, the molar concentration of polyvinyl pyrrolidone is 0.5-3 mol / L, and the volume ratio of ethanol, isopropanol and ethylene glycol is 1:(1-2):(3-8).

6. The method for preparing a vanadium dioxide temperature control film according to claim 1 or 2, characterized in that: The soluble vanadium salt is vanadyl sulfate, the precipitant is urea, the dopant is a tungsten dopant and a molybdenum dopant, the molar ratio of the tungsten dopant to the molybdenum dopant is 1:1-8:1, the tungsten dopant is ammonium tungstate, and the molybdenum dopant is ammonium molybdate.

7. A vanadium dioxide temperature control film, characterized in that: The method is prepared by the preparation method described in any one of claims 1 to 6.

8. A method for preparing vanadium dioxide thermochromic glass, characterized in that: The following steps are involved: S10: forming a vanadium dioxide temperature control film on a glass substrate using the preparation method described in any one of claims 1 to 6; S20: coating a mixture of methyl methacrylate and acrylic acid on the vanadium dioxide temperature control film, and forming a transparent protective film through ultraviolet light exposure to obtain vanadium dioxide thermochromic glass.

9. The method for preparing vanadium dioxide thermochromic glass according to claim 8, characterized in that: In the mixture of methyl methacrylate and acrylic acid, the volume ratio of methyl methacrylate to acrylic acid is 1:1-5:1; The coating thickness of the mixture is 100-500 μm; The UV exposure time is 3-10 minutes.

10. A vanadium dioxide thermochromic glass, characterized in that: The method is prepared by the preparation method described in any one of claims 8 to 9.

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